15,856 research outputs found
Estimation of bearing contact angle in-situ by X-ray kinematography
The mounted, preloaded contact angle of the structural bearings in the assembled design mechanical assembly was measured. A modification of the Turns method is presented, based upon the clarity and definition of moving parts achieved with X-ray technique and cinematic display. Contact angle is estimated by counting the number of bearings passing a given point as a function of number of turns of the shaft. Ball and pitch diameter variations are discussed. Ball train and shaft angle uncertainties are also discussed
Friendship and Natural Selection
More than any other species, humans form social ties to individuals who are
neither kin nor mates, and these ties tend to be with similar people. Here, we
show that this similarity extends to genotypes. Across the whole genome,
friends' genotypes at the SNP level tend to be positively correlated
(homophilic); however, certain genotypes are negatively correlated
(heterophilic). A focused gene set analysis suggests that some of the overall
correlation can be explained by specific systems; for example, an olfactory
gene set is homophilic and an immune system gene set is heterophilic. Finally,
homophilic genotypes exhibit significantly higher measures of positive
selection, suggesting that, on average, they may yield a synergistic fitness
advantage that has been helping to drive recent human evolution
Bit error rate measurement above and below bit rate tracking threshold
Bit error rate is measured by sending a pseudo-random noise (PRN) code test signal simulating digital data through digital equipment to be tested. An incoming signal representing the response of the equipment being tested, together with any added noise, is received and tracked by being compared with a locally generated PRN code. Once the locally generated PRN code matches the incoming signal a tracking lock is obtained. The incoming signal is then integrated and compared bit-by-bit against the locally generated PRN code and differences between bits being compared are counted as bit errors
Refactoring Legacy JavaScript Code to Use Classes: The Good, The Bad and The Ugly
JavaScript systems are becoming increasingly complex and large. To tackle the
challenges involved in implementing these systems, the language is evolving to
include several constructions for programming- in-the-large. For example,
although the language is prototype-based, the latest JavaScript standard, named
ECMAScript 6 (ES6), provides native support for implementing classes. Even
though most modern web browsers support ES6, only a very few applications use
the class syntax. In this paper, we analyze the process of migrating structures
that emulate classes in legacy JavaScript code to adopt the new syntax for
classes introduced by ES6. We apply a set of migration rules on eight legacy
JavaScript systems. In our study, we document: (a) cases that are
straightforward to migrate (the good parts); (b) cases that require manual and
ad-hoc migration (the bad parts); and (c) cases that cannot be migrated due to
limitations and restrictions of ES6 (the ugly parts). Six out of eight systems
(75%) contain instances of bad and/or ugly cases. We also collect the
perceptions of JavaScript developers about migrating their code to use the new
syntax for classes.Comment: Paper accepted at 16th International Conference on Software Reuse
(ICSR), 2017; 16 page
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